Fault diagnosis and analysis in the use of intelligent differential pressure transmitters - Database & Sql Blog Articles

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The intelligent differential pressure transmitter is a widely used device in industrial automation systems, especially in applications requiring precise measurement of pressure differences. Jiangsu Xianda Instrument provides an in-depth explanation of the working principle, common measurement methods, installation techniques, and essential precautions for using this equipment. Additionally, it covers fault diagnosis and troubleshooting strategies to ensure reliable performance and minimize downtime.

Understanding how to identify and resolve issues quickly is crucial for maintaining smooth operations. This guide will help users recognize typical problems and apply effective diagnostic techniques. Whether you're a technician or an engineer, these insights will enhance your ability to manage and maintain intelligent differential pressure transmitters efficiently.

First, the working principle of an intelligent differential pressure transmitter:

The differential pressure from the two sides of the pressure guiding tube is directly applied to the dual-sided isolating diaphragm of the transmitter sensor. This pressure is then transmitted through the sealing liquid within the diaphragm to the measuring component. The measuring component converts the differential pressure signal into an electrical signal, which is then sent to the converter. The converter amplifies or processes the signal and outputs a standard electrical signal, such as 4-20 mA or a digital signal, for further use in control systems.

Second, fault diagnosis and analysis methods when using intelligent differential pressure transmitters:

During the operation of the transmitter, various faults may occur. Timely identification and analysis of these issues are essential for continuous production. Many of the troubleshooting techniques used for intelligent differential pressure transmitters can also be applied to traditional pressure transmitters due to their similar operational principles. Based on practical experience, we have compiled some effective diagnostic methods and procedures that can assist in identifying and resolving problems efficiently.

1. Investigation method: Review any incidents that occurred before the fault, such as fire, smoke, unusual odors, power fluctuations, lightning strikes, moisture exposure, incorrect operations, or improper maintenance. These factors can often contribute to the failure of the transmitter.

2. Intuitive method: Examine the external condition of the circuit, check for leaks in the pressure guiding tubes, look for signs of overheating, and verify the status of the power switch. Visual inspection can reveal many potential issues at a glance.

3. Detection method:

a. Disconnection detection: Isolate the suspected faulty section from the rest of the system to determine if the problem disappears. If it does, the issue lies in that section. For example, if a smart HART pressure transmitter fails to communicate, disconnect it from the main unit and power it using a field power supply to check whether electromagnetic interference around 2 kHz is affecting the communication.

b. Short-circuit detection: In safe conditions, short-circuit the relevant part of the circuit. For instance, if the output of the differential pressure transmitter is too low, disconnect the pressure guiding tube and directly connect the first pressure tap to the transmitter on both sides to observe the output and determine if there is a blockage or leakage in the pilot line.

c. Replacement test: Replace the suspected faulty component with a known good one to identify the source of the problem. For example, if the transmitter board is suspected to be faulty, temporarily replace it to see if the issue is resolved.

d. Division detection: Divide the measurement loop into smaller sections, such as power supply, signal output, signal transmission, and signal detection. Inspect each section sequentially, starting from the simplest to the most complex, and from the surface to the internal components, to narrow down the fault location effectively.